Films are used in a wide variety of applications where the engineered qualities of the apertured and/or unapertured film can be advantageously employed as a component substrate. The use of selected thermoplastic polymers in the construction of film products, selected treatment of the polymeric films (either while in melt form or in an integrated structure), and selected use of various mechanisms by which the film is integrated into a useful construct, are typical variables by which to adjust and alter the performance of the resultant polymeric film product.
The formation of finite thickness films from thermoplastic polymers is a well known practice. Thermoplastic polymer films can be formed by either dispersion of a quantity of molten polymer into a mold having the dimensions of the desired end product, known as a thermo-formed or injection-molded film, or by continuously forcing the molten polymer through a die, known as an extruded film. Extruded thermoplastic polymer films can either be formed such that the film is cooled then wound as a completed product, or dispensed directly onto a substrate material to form a composite material having performance of both the substrate and the film layers.
The application of the extruded film directly onto a substrate material imparts the substrate material with enhanced physical properties. It is known in the art that the application of a thermoplastic polymer film having suitable flexibility and porosity onto a nonwoven fabric results in a composite material having significant barrier properties and is suitable for disposable protective garment manufacture.
Film substrates are desirable for a variety of end-use applications due to the barrier performance such substrates can provide. Films have proven to be particularly suitable for a variety of medical, hygiene, and industrial applications and when utilized in a laminate construct, permits cost-effective, disposable use. Use of such materials for diapers, sanitary napkins, medical wipes, and the like has become increasingly widespread, since the use of a nonwoven fabric constructs can provide a desired softness that may be required for specific hygiene applications, such as a backsheet for a disposable absorbent garment.
The use of disposable sanitary articles, and in particular disposable diapers, has come into public favor over the past twenty years due to the convenience of use. There is an ever-present demand to improve the comfort and aesthetics of the article. Recently, a soft, cloth-like backsheet has become desirable so as to reduce the amount of noise made by the diaper during an infant's activities, as well as during donning and doffing the disposable diaper. Further, it has become desirable to impart a graphical image onto the backsheet of the diaper, such as figures, animals or characters, in order to impart aesthetic appeal to the disposable article.
Traditionally, the method of making a printed backsheet for an absorbent article consists of bonding a roll of previously printed thermoplastic film to a pre-formed roll of nonwoven fabric. The film tends to have a heavier basis weight due to the problems associated with unwind tension and breakage with lighter weight films, which slows the printing and bonding processes. A need exists for an in-line process that is more efficient and allows for a lighter basis weight film to be utilized with a nonwoven that exhibits a cloth-like feel, wherein the resultant laminate exhibits the necessary barrier performance, as well as conformability for comfort when used as a backsheet for an absorbent article.